Designing and codes
NFPA 72 (2019) Reference Points:
17.7.3.6 Air Sampling–Type Smoke Detector
17.7.3.6.1 General
17.7.3.6.1.1 In the absence of specific performance-based design criteria, each sampling port of an air
sampling–type smoke detector shall be treated as a spot-type smoke detector for the purpose of location
and spacing in accordance with 17.7.3.
17.7.3.6.2 Pipe Network.
17.7.3.6.2.1 Maximum air sample transport time from the farthest sampling port to the detector shall not
exceed 120 seconds.
17.7.3.6.2.2 Sampling pipe networks shall be designed on the basis of, and shall be supported by,
computer-based fluid dynamics design calculations to ensure required performance.
17.7.3.6.2.3 The sampling pipe network design calculations shall include pressure, volumetric flow, and
alarm sensitivity at each sampling port.
17.7.3.6.2.4 Software applications for the design of pipe networks shall be listed for use with the
manufacturer’s equipment.
Designing and codes
17.7.3.6.2.7 If provided, test ports at the end (most remote location) of a pipe run installed in the pipe
network solely for the purpose of validating consistency in performance (also referred to as benchmark
test points) shall be included in the design calculations and allowed, but not required, to comply with the
requirements of 17.7.3.6.2.
17.7.3.6.2.9 Pipe network materials, sizing and installation shall be in accordance with the manufacturer’s
published requirements and suitable for use in the environment in which they are installed.
17.7.3.6.2.10 Where used, capillary tubing shall be sized and affixed in accordance with the
manufacturer’s published instructions and computer-based design calculations.
17.7.3.6.3 Installation and Spacing
17.7.3.6.3.1 Air sampling pipe network fittings shall be installed air-tight and permanently affixed.
17.7.3.6.3.2 Sampled air shall be exhausted to a lessor or equal pressure zone. The pressure differential
between the sampled air and detector exhaust shall not exceed the manufacturer’s published
instructions.
17.7.3.6.3.3 Supports for sampling pipe shall be in accordance with the air sampling-type smoke detector
manufacturer’s published instructions.
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